there is a bug in windows 10 open gl on multiscreen setups ... I'm not able to figure out where / how it is happening but s3d is not only app affected (same issue with slic3r, prusa slicer, netfabb..) and solution for s3d is to delete all the registry keys under "HKEY_CURRENT_USER\Software\Simplify3D\S3D-Software\" that are named "geometry". This resets the location where s3d tries to open window at and everything works until you move any of the s3d window to your "non primary screen" and close it, next time you try to open that it will not work.
no clue how to solve this on system level, so far everyone I know having this problem is windows10 and nvidia.
integrates with Simplify3D and allow you to
Calculate print time accurately (acceleration, max speed, junction deviation all taken into consideration)
Embed M117 codes into G-Code
Upload your G-Code directly to Octoprint
open source and unlicence